The price at which a specific derivative contract can be exercised. Strike prices is mostly used to describe stock and index options, in which strike prices are fixed in the contract. For call options, the strike price is where the security can be bought (up to the expiration date), while for put options the strike price is the price at which shares can be sold.
The difference between the underlying security’s current market price and the option’s strike price represents the amount of profit per share gained upon the exercise or the sale of the option. This is true for options that are in the money; the maximum amount that can be lost is the premium paid.
Also known as the “exercise price”.
Base on this example, GOOG 510 Call, the strike price of 510 means the stock can be bought for $510 per share and vice versa for put option, allows the buyer to sell the stock at $510. The strike price also helps us to identify whether an option is In the Money(ITM), At the Money(ATM) or Out of the Money(OTM) when compared to the price of the underlying security.